Introduction
Have you
ever got
tired of
loading
Dynamic Link
Libraries
the long
way, with
the usual
steps
LoadLibrary
,
and
GetProcAddress,
then you
have to
check for
each
function
address if
they are
NULL
,
and don't
mention
about
casting the
function
pointer and
hard ways
that make
your brain
strain. And
wish there
was an
easier way
to get
around
things? Well
this will
just do that
in a way and
is about the
easiest way
I know of
actually
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Code
BOOL GetProcAddresses( HINSTANCE *hLibrary,
LPCSTR lpszLibrary, INT nCount, ... )
{
va_list va;
va_start( va, nCount );
if ( ( *hLibrary = LoadLibrary( lpszLibrary ) )
!= NULL )
{
FARPROC * lpfProcFunction = NULL;
LPSTR lpszFuncName = NULL;
INT nIdxCount = 0;
while ( nIdxCount < nCount )
{
lpfProcFunction = va_arg( va, FARPROC* );
lpszFuncName = va_arg( va, LPSTR );
if ( ( *lpfProcFunction =
GetProcAddress( *hLibrary,
lpszFuncName ) ) == NULL )
{
lpfProcFunction = NULL;
return FALSE;
}
nIdxCount++;
}
}
else
{
va_end( va );
return FALSE;
}
va_end( va );
return TRUE;
}
So since we
now have the
main core to
this
article,
lets now
look at how
to use this
with a short
sample that
was compiled
as a Windows
console
application.
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Code
#include <windows.h>
typedef int ( WINAPI *MESSAGEBOX )
( HWND , LPCSTR, LPCSTR, DWORD );
typedef int ( WINAPI *MESSAGEBOXEX )
( HWND , LPCSTR, LPCSTR, DWORD , WORD );
void main(void)
{
MESSAGEBOX lpfMsgBox = NULL;
MESSAGEBOXEX lpfMsgBoxEx = NULL;
HINSTANCE hLib;
if(GetProcAddresses( &hLib, "User32.dll", 2,
&lpfMsgBox, "MessageBoxA",
&lpfMsgBoxEx, "MessageBoxExA" ) )
{
lpfMsgBox( 0, "Test1", "Test1", MB_OK );
lpfMsgBoxEx( 0, "Test2", "Test2", MB_OK,
MAKELANGID( LANG_ENGLISH, SUBLANG_ENGLISH_US ) );
}
if ( hLib != NULL )
FreeLibrary( hLib );
}